Six global powers and Iran are negotiating a deal that would rein in Iran's nuclear program, reducing Western fears that the Islamic republic could develop nuclear weapons, in exchange for relief from sanctions that are hurting its economy.

After years of talks, they are seeking a political framework agreement by the end of March and a full deal by June 30.

A U.S. official said Secretary of State John Kerry "reiterated our desire to move toward a political framework by the end of March" during a meeting with Zarif in Munich on February 6.

The Russian Foreign Ministry said Lavrov and Zarif also discussed bilateral ties and the situation in the Middle East.